D.c. keyed high low select preference system for polyphonic electrical musical instruments

ABSTRACT

A transistorized high-low note select system for keyboard type electrical musical instruments which provides for direct current operation with or without control of the attack and decay envelope and supplies the alternating current signals for the highest and/or lowest notes of a group of notes played together respectively to a high note lead or a low note lead or to independent leads for each. Primarily, this is for the purpose of supplying the high note signal of group of keys played simultaneously to be sounded as a solo note, or high and low notes of an accompaniment chord to be sounded in unison or with frequency division as a pair of bass notes one or two octaves down from a three or four note chord being held on a keyboard for example. The system may also be used to supply the lowest note with frequency division as a single bass note or for similar purposes. The keyboard may be conventional.

United States Patent [191 Schrecongost 1 D.C. KEYED HIGH LOW SELECTPREFERENCE SYSTEM FOR POLYPHONIC ELECTRICAL MUSICAL INSTRUMENTS [75]Inventor: Ray B. Schrecongost, Park Ridge,

[73] Assignee: Hammond Corporation, Deerfield,

- Ill.

[22] Filed: July 17, 1972 [21] Appl. No.1 272,437

[52] U.S. Cl. 84/l.01, 84/DIG. 2 [51] Int. Cl. G101! 1/02 [58] Field ofSearch 84/1.0l, 1.11, 1.12,

84/l.17, l.l9-l.24, DIG. 2, DIG. 23; 307/23l,'233, 241-243 [56]References Cited UNITED STATES PATENTS 2,429,226 10/1947 I-Ianert84/l.2l 2,468,062 4/1949 I-lanert..... 84/1.2 2,645,968 7/1953 I-lanert84/l.22 2,933,004 4/1960 Hanert 84/1.0l 3,051,032 8/1962 I-lanert84/1.19 3,283,057 11/1966 Campbell 84/1.0l 3,476,864 11/1969 Munch etal.... 84/D1G. 2 3,511,917 5/1970 Mallett 84/1.0l 3,538,804 11/1970George 84/l.0l 3,665,089 5/1972 Stearns 84/l.0l 3,719,767 3/1973Matumoto et a]. 84/l.01 2,710,555 6/1955 Martin 84/l.01 2,874,286 2/1959Bode 84/DIG. 2

[ Oct. 16, 1973 Primary Examiner-Richard B. Wilkinson AssistantExaminerStanley J. Witkowski AttorneyWilliam F. Gradolph et a1.

[5 7 ABSTRACT A transistorized high-low note select system for keyboardtype electrical musical instruments which provides for direct currentoperation with or without control of the attack and decay envelope andsupplies the alternating current signals for the highest and/or lowestnotes of a group of notes played together respectively to a high notelead or a low note lead or to independent leads for each. Primarily,this is for the purpose of supplying the high note signal of group ofkeys played simultaneously to be sounded as a solo note, or high and lownotes of an accompaniment chord to be sounded in unison or withfrequency division as a pair of bass notes one or two octaves down froma three or four note chord being held on a keyboard for example. Thesystem may also be used to supply the lowest note with frequencydivision as a single bass note or for similar purposes. The keyboard maybe conventional.

7 Claims, 1 Drawing Figure D.C. KEYED HIGH LOW SELECT PREFERENCE SYSTEMFOR POLYPIIONIC ELECTRICAL MUSICAL INSTRUMENTS BACKGROUND OF THEINVENTION 1. Field of the Invention High and/or low note select systemsfor keyboard type electrical musical instruments and instruments whichincorporate such systems.

2. Description of the Prior Art Keyboard type electrical musicalinstruments, such as electric or electronic organs, for example, havefor a number of years incorporated what is referred to generally in thistechnology as preference circuits. For example of such typicalinstruments and preference systems see .I. M. Hanert, US. Pat. Nos.3,051,032; 2,933,004; 2,468,062; 2,429,226; and 2,645,968. For a moremodern instrument using such a system see Tennes and Kern US. Pat. No.3,567,838 and for a high-low note preference system which it is believedis the prior system most similar to the present invention, see H. E. W.Bode, US. Pat. No. 2,874,286 which is incorporated by reference in theTennes et al., US. Pat. No. 3,567,838, referred to above.

For purpose of orientation, the present invention may be considered asan improvement over the system of Bode, U.S. Pat. No. 2,874,286 and as asubstitute therefor, for example, in musical instruments of the type ofTennes et al. U.S. Pat. No. 3,567,838.

SUMMARY OF THE INVENTION Briefly, the system of the previously referredto Tennes et al patent provides a keyboard type musical instrument inwhich holding the keys of a chord of three or four notes with the lefthand supplies the appropriate three of four note signals together to achord lead. Simultaneously, a preference system of the Bode typesupplies the signal for the lowest note of the group to a low noteselect lead and the signal for the highest note of the group to a highnote select lead. An automatic rhythm system of the type which soundsdrum, cymbal, blocks, and similar untuned sounds according to any ofseveral selected programs is connected such that at appropriateintervals during the program which may include various of the untunedinstrumental sounds, the programmer also sounds whatever signals are onthe chord lead, the low note select lead and the high note select lead.Usually, the signals on the low note select lead and the high noteselect lead are passed through one or preferably two stages of binaryfrequency division so that the selected low and high notes sound one orpreferably two octaves down from the chord. Overall, therefore, theeffect is such that by simply holding the keys for a three or four notechord with the left hand, and at appropriate times changing from onechord to another, the system automatically according to whatever programis selected, keys orsounds the chord, a low bass note and a high bassnote. This eliminates the need to play the chord at the proper time andalso eliminates the need for bass pedals and the skill normally requiredfor their actuation.

The previously referred to Bode preference system is based upon what isknown as A.C. keying, that is, the playing key contacts make and breakthe alternating current signal circuits. There are disadvantagesassociated with A.C. keying, such as problems'with transients andparticularly an inability to exercise control over the keying envelope.There is no convenient way for sustaining the tone with a graduallydecaying envelope after a key has been released, for example. Thepresent invention overcomes such problems by providing a D.C. actuatedpreference circuit. That is, the playing keys make and break a D. C.circuit which turns transistors on and off with or without sustain asdesired. For instance, the control D.C. can charge a capacitor whichwill hold the signal circuit through the preference network on longenough to allow percussion or sustain keying in a following circuit.Thus, the substitution of DC. actuation or keying for A.C. keyingpermits the designer to exercise envelope control which is not possiblewith A.C.keying.

Additionally, the provision of D.C. acutation makes it possible todesign an organ system such that each of the playing keys needs only oneset of make contacts. These make a DC. control circuit for theparticular key and this control circuit can be routed to any number ofkeyers for various different purposes. Thus, DC. control signals for agroup of keys played together supply note signals for the lowest, thehighest or both notes of the group. These selected note signals, with orwithout sustain, can be frequency divided, multiplied, formanted and canhave any desired envelope characteristic provided by a followingpercussive or sustain keyer.

These and other advantages of DC. operation are well appreciated in thisart and D.C. keyers are in general use. So far as is known, however, theapplication of DC. operation to preference circuits has not previouslybeen successfully accomplished.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. ii is a circuit diagram of apreference system which includes features of the present invention; and

FIG. 2 is a diagram showing the circuit of FIG. I modified to providesustain of the envelope after a playing key has been released.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. I of the drawings agroup of transistors are indicated individually at A, B, C, I), N. Eachof these is the active element of a keyer or gate for one note of theportion of the musical instrument to which the preference system of theinvention is applied. For example, the preference system may be appliedto the accompaniment section of an organ and cover the lowest group oftwenty playing keys, such that if a chord of three or four keys isplayed within this section, the preference system will select the lowestand the highest notes of any such chord.

The transistors A-D may be considered representative of the lowest fourkeyers for this section and N the highest, it being understood thatthere will be others between D and N which are not shown since all areidentical.

The base of transistor A is connected to ground, which here representsthe other side of the circuit, through a resistor and through resistor12 to one side of a set of playing key contacts 14, the other side ofwhich is connected to a DC. keying bus 16. Branch loads 15 are the mainkeying leads for connection to the other customary organ keyers, notshown which key the noteto be played in the usual organ fashion, thatis, in any of the regular organ modes. The emitter is connected toground through a resistor 18 and to a terminal 20 which may beconsidered as the source of the particular music signal to be keyed.Each of these terminals, 20, is connected to one side of the appropriatetone signal generator. The other side of each generator, as iscustomary, is connected to the other side of the circuit, normallyreferred to as ground. One of these generators, (all are alike exceptingfor frequency) for the F signal, is indicated at 21. All of thetranisitors A'N are similarly connected excepting that the frequenciesapplied to terminals 20 are a semitone apart as indicated by thedesignations F,, F F F F Similarly also, the playing key contacts 14 areactuated by different playing keys, each of which is appropriate to itsparticular tone signal.

The transistor A, for keying the lowest note of the group, has itscollector connected through a resistor 22 to a low note select outputterminal 24, connected in turn to the input of a preamplifier 26 havingan output The collector of the second transistor B, is connected to thecollector of A through a resistor 28 and to the collector of C through aresistor 30. C collector is also connected through a resistor 32 to thecollector of D which is connected to the collector of the next in theseries'through resistor 34, and so on to the collector of transistor N,the last in the series. The collector of transistor N is connectedthrough resistor 36 to a high note select output terminal 38. Thisoutput terminal is connected to the input of preamplifier 40 having anoutput 41.

Suitable values for the constants of this particular circuit are asfollows. Resistors 10, 10 K; resistors 18, 100 ohms; resistors 12, 100K; and resistors 22, 28, 30, 32, 34 and 36, 22 K. The keying voltage onbus '16 may suitably he -28 v.

The preamplifiers 26 and 40 have a relatively high input impedance ofthe order of ten times or more of the total of the resistance in theline between the two output terminals 24 and 38. If, as in the examplegiven, there are twenty keyers, and, therefore, 21' resistors in seriesof 22 K each, a total of 462 K,a suitable value for the input impedanceof the amplifiers is megohms or so. v

The outputs 27 and 41 from the preamplifiers may be connected to anydesired circuits such as frequency dividers and suitable formantsto'obtain bass notes re- .lated to the chord being held for example.

automatic programmer can at appropriate intervals switch thepreamplifier outputs to a bass note frequency divider leading to theoutput system of the organ or if desired, the programmer or amultivibrator or some similar system can switch the low and highterminals 24 and 38 to the input of a single preamplifier. It will beappreciated, of course, that this invention is concerned with thepreference system and not particularly with the specific use made of thehigh and low note signals selected by the system,

The system operates as follows. Assuming the playing key contacts 14 areclosed for transistor A, this applies the -28 v. on bus 16 to the to onevoltage divider composed of 100 K resistor 12 and I0 K resistor 10. Thevoltage appearing at the base' of transistor A is, therefore, about -2.8v. which causes the transistor to conduct. The portion of the F,signalat terminal not grounded through resistor 18 is therefore conducted tothe junction between resistors 22 and 28. Because of the high impedanceof the amplifiers 26 and 40, it makes little difference whether thesignal passes through resistor 22 to amplifier 26 or whether it passesthrough twenty resistors of the same value to amplifier 40. In one casethe resistance is 22 K whereas on the other it is 440 K, but both aresmall as compared with the amplifier input impedances of 5 megohms orso. THe F, signal from terminal 20, therefore, appears at bothpreamplifier output terminals 27 and 41 at about the same strength.

If new it is assumed that key contacts 14 are closed for signals F, andF,,, (transistors A and N) the F, signal appears at terminal 24 throughresistor 22 (22 K) and signal F appears at terminal 38 through resistor36 (22 K). Also, the F, signal passes through the group of resistors 28,30, 32, etc. to appear at the junction of resis for 36 with the lead tothe collector transistor N. Since the resistance from this point toterminal 38 is 22 K (resistor 36) and transistor N is conductive. andthe resistance 18 to ground is only ohms, the F, signal is attenuatedapproximately by the ratio 100 plus the resistance of the transistordivided by 22,000. This is sufficient to attenuate the F, signalappearing at terminal 38 such that it is completely masked by the Fsignal. Similarly, the F signal to terminal 24 is essentially groundedthrough transistor A and its resistor 18. The high note signal, Ftherefore, appears at terminal 41 and the low note signal at terminal27.

If a three or four note chord is held, those signals supplied to theoutput group of series connected 22 K resistors anywhere between thehighest and the lowest note signals of the chord will be effectivelygrounded for practical purposes through the transistors and resistors 18of the highest and lowest transistors of the group which have been madeconductive-by closing their key contacts 14. Thus, regardless of'thenumber of keys held simultaneouly, only the note signal for the lowestof the group will appear at terminal 27 and only the signal for thehighest key held will appear at terminal 41. It should be noted thatwhether a keyed signal appears at the output or not is determinedwithout affecting the impedance of the DC. keying circuits involved, orthe impedance of the signal sources, and that the impedance to the otherside of the circuit through low value resistors 18 is essentiallyindependent of the impednace of the signal generators connected betweenterminals 20 and the other side of the circuit.

The modified arrangement of FIG. 2 shows the circuit of a singletransistor and is like those of FIG. ll excepting that a capacitor 50,shown connected across resistors 10 and 12, will remain charged afterkey release. A similar capacitor is connected across each of the otherpairs of resistors 10 and 12 of the preference circuit. With thismodification, closing key contacts 14 charges the capacitor 50 and turnson the transistor. When the playing key is released and the contactsopen, capacitor 50 will remain charged, and consequently the note signalwill remain on, long enough for subsequent gating or envelope shaping ofthe output signal or the frequency divider outputs by means of aconventional unitary keying system. A- conventional snubbing circuit maybe required to insure that only the last-played note remains on. As anexample, the preference system with this simple holding circuit can havethe preamplifier outputs connected through unitary keyers, which may beconventional. These following unitary keyers can give the selected notesany desired envelope characteristic such as percussive (a struck orplucked string effect) or sustain (a gradual decay after the key isreleased) or something similar, the purpose of the capacitors 50 beingto hold the note after key release long enough for the unitary keyers toimpart their characteristic envelope. This simple holding feature forthe preference circuit is illustrative of the possibilities for controlof the keying envelope which is characteris tic of this invention andone of its important features.

With an appropriate adjustment of values, the transistors shown may beany of several types including field effect transistors if desired.

Although the preference circuit of this invention has been described inconjunction with a system which selects both the high and low notes of agroup of keys played together, it will be appreciated that the systemsomewhat abridged can supply only the high or the low note if that isall that is desired. For example, if only the high note is needed, thelow end portion of the circuit including the resistor 22, terminal 24and preamplifier 26 can be eliminated. It will also be appreciated thateven though emphasis has been placed upon use of the system to supplyhigh and low bass notes, this is for the purpose of illustrating atypical embodiment. As mentioned earlier, preference circuits have otheruses and it is considered that the invention is in the D.C. preferencecircuit itself, rather than in the uses to which the output of thecircuit is put.

, I claim:

I. In a preference system, a plurality of sources for a group ofalternating current signals, a plurality of actuated control elementsone for each of said signals, a plurality of transistors, one for eachof said signals, a source of D.C. keying potential, D.C. circuit meansincluding said control elements connected individually from said D.C.source to said transistors to cause individual transistors to conductwhen aappropriate individual control elements are actuated,veach of saidtransistors having an input circuit connected to receive a signal fromone of said sources and an output, an output line consisting of a groupof series connected substantially identical resistors with one end ofsaid group connected to a terminal, the outputs of said transistorsbeing connected individually to the junctions between said resistors,high impedance output circuit means connected to said terminal, each ofsaid input circuits for said transistors having a low impedanceconnection in shunt with its signal source, the impedance of said highimpedance output circuit means being many times the total impedance ofall of the series connected resistors and the impedance of each of saidseries connected resistors being many times the impedance of each ofsaid low impedance connections.

2. The system of claim I in which each of said input circuits includes alow impedance resistor connected between the transistor signal input andground.

3. The system of claim 1 including sustain circuits for said transistorsfor retaining said transistors in conducting condition for a selectedperiod after said control elements are deactuated, each of said sustaincircuits including a capacitor connected to be charged when the controlelement is actuated and to discharge at a controlled rate when thecontrol element is deactuated.

4. In a high-low note select preference system, a plurality of sourcesfor a group of musical tone signals, a plurality of playing keys one foreach of said signals, each of said keys having a contact set, aplurality of transistors, one for each of said signals, a source of D.C.keying potential, D.C. circuit means including said contact setsconnected individually from said D.C. source to said transistors tocause individual transistors to conduct when appropriate playing keysare actuated, each of said transistors having a signal input circuitconnected to receive a signal from one of said sources and an outputline consisting of a group of series connected substantially identicalresistors with the first of said group connected to a low note selectterminal and the last of said group connected to a high note selectterminal, said group of resistors having one more resistor than thereare transistors, the output of the transistor for the lowest note of thegroup being connected to the junction between the first and secondresistor, the output form the transistor for the next higher note beingconnected to the junction between the second and third resistor, theoutput from the transistor for the next higher note being connected tothe junction between the third and fourth resistor and so on for theoutputs of all of said transistors with the output of the transistor forthe highest note of the group connected between the last and the next tolast resistors of said group, high impedance output circuit meansconnected to said low note select and said high note select terminals,each of said signal input circuits for said transistors having a lowimpedance connection in shunt with the signal source, the impedance ofsaid high impedance output circuit means being many times the totalimpedance of all the series connected resistors and the impedance ofeach of said series connected resistors being many times the impedanceof each of the low impedance connections around the signal sources.

5. The system called for in claim 4 in which each of said signal inputcircuits includes a low impedance resistor connected between thetransistor input and ground.

6. The system called for in claim 4 in which said D.C. circuit meansincludes a series resistor network and capacitor in paralled theretoconnected between each said contact sets and the other side of thecircuit, and an intermediate voltage point on said resistor networkconnected to said transistor.

7. The system called for in claim 5 in which said D.C. circuit meansincludes a series resistor network and capacitor in parallel theretoconnected between each said contact sets and the other side of thecircuit, and an intermediate voltage point on said resistor networkconnected to said transistor.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,766,305Dated ctober 16, 1973 Inventor) Ray B. Schrecongost It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Abstract, line 9, before "group" insert -a--. Col. 1, line 36, "of"should be or-. Col. 4, line 9, "THe" should be I'he-;

line 18, after "collector" insert of-; line 20, should be I line 47,"impednace" should be impedance-.

Col. 6, line 17, after "output" insert an output-;

line 25, "form" should be ---from-'.

Signed and sealed this 21st day of May 197 (SEAL) Attest:

EDWARD PLFLETCHLIELJI'L. C. MARSHALL Attesting; Officer Commissioner ofPatents FORM (169) USCOMM-DC 60376-P69 9 U.5. GOVEfiNMENT PRINTINGOFFICE 199 0-367334.

1. In a preference system, a plurality of sources for a group ofalternating current signals, a plurality of actuated control elementsone for each of said signals, a plurality of transistors, one for eachof said signals, a source of D.C. keying potential, D.C. circuit meansincluding said control elements connected individually from said D.C.source to said transistors to cause individual transistors to conductwhen aappropriate individual control elements are actuated, each of saidtransistors having an input circuit connected to receive a signal fromone of said sources and an output, an output line consisting of a groupof series connected substantially identical resistors with one end ofsaid group connected to a terminal, the outputs of said transistorsbeing connected individually to the junctions between said resistors,high impedance output circuit means connected to said terminal, each ofsaid input circuits for said transistors having a low impedanceconnection in shunt with its signal source, the impedance of said highimpedance output circuit means being many times the total impedance ofall of the series connected resistors and the impedance of each of saidseries connected resistors being many times the impedance of each ofsaid low impedance connections.
 2. The system of claim 1 in which eachof said input circuits includes a low impedance resistor connectedbetween the transistor signal input and ground.
 3. The system of claim 1including sustain circuits for said transistors for retaining saidtransistors in conducting condition for a selected period after saidcontrol elements are deactuated, each of said sustain circuits includinga capacitor connected to be charged when the control element is actuatedand to discharge at a controlled rate when the control element isdeactuated.
 4. In a high-low note select preference system, a pluralityof sources for a group of musical tone signals, a plurality of playingkeys one for each of said signals, each of said keys having a contactset, a plurality of transistors, one for each of said signals, a sourceof D.C. keying potential, D.C. circuit means including said contAct setsconnected individually from said D.C. source to said transistors tocause individual transistors to conduct when appropriate playing keysare actuated, each of said transistors having a signal input circuitconnected to receive a signal from one of said sources and an output, anoutput line consisting of a group of series connected substantiallyidentical resistors with the first of said group connected to a low noteselect terminal and the last of said group connected to a high noteselect terminal, said group of resistors having one more resistor thanthere are transistors, the output of the transistor for the lowest noteof the group being connected to the junction between the first andsecond resistor, the output from the transistor for the next higher notebeing connected to the junction between the second and third resistor,the output from the transistor for the next higher note being connectedto the junction between the third and fourth resistor and so on for theoutputs of all of said transistors with the output of the transistor forthe highest note of the group connected between the last and the next tolast resistors of said group, high impedance output circuit meansconnected to said low note select and said high note select terminals,each of said signal input circuits for said transistors having a lowimpedance connection in shunt with the signal source, the impedance ofsaid high impedance output circuit means being many times the totalimpedance of all the series connected resistors and the impedance ofeach of said series connected resistors being many times the impedanceof each of the low impedance connections around the signal sources. 5.The system called for in claim 4 in which each of said signal inputcircuits includes a low impedance resistor connected between thetransistor input and ground.
 6. The system called for in claim 4 inwhich said D.C. circuit means includes a series resistor network andcapacitor in paralled thereto connected between each said contact setsand the other side of the circuit, and an intermediate voltage point onsaid resistor network connected to said transistor.
 7. The system calledfor in claim 5 in which said D.C. circuit means includes a seriesresistor network and capacitor in parallel thereto connected betweeneach said contact sets and the other side of the circuit, and anintermediate voltage point on said resistor network connected to saidtransistor.